EP3733512B1 - Method and device for lifting a load - Google Patents

Description

The present invention relates to a method and a device for lifting a load, with at least one aerial drone carrying at least part of the load.

More recently, it has been considered to use aerial drones to lift loads and thus be able to carry out lifting tasks that were traditionally carried out by cranes more flexibly in order to reduce or completely avoid the restrictions and hassle of crane operation.

The writings US 2009/0299551 A1 , US 9,079,662 B2 and US 9,205,922 B1 describe lifting loads using several flying drones in order to have sufficient lifting power available for heavier loads, with various control measures being taken to prevent the flying drones from colliding with one another and to direct the load along a desired trajectory. From Scripture WO 2016/068767 A1 It is also known to use a multicopter to lift heavy loads, the rotors of which are driven by a gas turbine via hydraulic drive trains, each of which has a hydrostat driven by the gas turbine and working as a pump and a hydrostat connected to the respective rotor and working as a motor . The speed of the rotors is controlled via control valves, through which excess pressure oil is drained if necessary.

For example, there are various lifting tasks on construction sites for which a crane must be delivered, set up, dismantled and transported away again. For example, these can be individual strokes in order to move certain building parts or construction tools to a certain area of a building to be built or converted. If no crane is otherwise required at the construction site, the crane must be set up specifically for this purpose.

Even if a crane is used on the construction site, special lifts may arise for which another crane is required, for example to erect the stationary, permanent construction crane.

To date, flying drones have been used in construction sites and other crane applications, such as container cranes or harbor cranes, primarily for additional auxiliary functions, in particular to fly cameras or similar imaging monitoring devices into position in order to monitor the crane operation or the lifting process carried out by the crane . In particular, the image provided by the camera attached to the flying drone can be displayed on a screen in the crane operator's cab in order to give the crane operator a different perspective on the crane hook.

However, if the drone is involved in lifting the load, controlling the drone is exposed to other influences and is significantly more difficult and complex. In particular, the load to which the flying drone is connected exerts considerable forces on the flying drone, which not only pull statically in the vertical direction, but also have horizontal components and can vary, for example, due to gusts of wind. In addition, pendulum movements and thus dynamic forces from the load can quickly move the drone into undesired positions or cause it to move.

Proceeding from this, the present invention is based on the object of creating an improved method and an improved device for lifting loads using a flying drone, which avoid the disadvantages of the prior art and further develop the latter in an advantageous manner. In particular, simple control of the flying drone should be achieved even under the influence of the load associated with the flying drone.

According to the invention, the stated object is achieved by a method according to claim 1 and a device according to claim 9. Preferred embodiments of the invention are the subject of the dependent claims.

It is therefore proposed to clamp several flying drones together to lift the load and to provide a common control for the several, so as not to have to control several flying drones with separate control means, so to speak, with multiple hands. The load is divided between several flying drones. In addition to the at least one flying drone, which carries at least part of the load, it is provided according to the invention that the load is connected to a further flying drone and is partially carried and/or directed by the further flying drone, the two flying drones being connected to one another by a common control device Controlling flight movements can be controlled in a coordinated manner. If the control device is actuated, for example, to fly an aircraft drone, a coordinated control signal is automatically generated in order to move the other aircraft drone in a corresponding manner.

If a load is lifted by a crane, for example in the form of a tower crane, a mobile telescopic crane or a harbor crane, several flying drones can be connected to the crane hook at the same time on the load to be lifted or can also be connected directly to the crane hook in order to lift in different ways to help the burden. For example, the load to be lifted can be lightened for the crane, for example in order to be able to lift a load that exceeds the load capacity or load capacity of the crane, so that the construction site operator can avoid having to set up a crane that is larger for this lifting task. The Flying drones can therefore perform a pure lifting function and lift a load together with a crane.

Multiple flying drones can carry the load or be connected to the load hook, whereby it may be advantageous, for example, to have at least one pair of flying drones on opposite sides of the load hook position and connect to the load or the load hook itself in order to be able to exert horizontal forces in approximately opposite directions on the load hook or the load attached to it or to be able to compensate for each other if, for example, only the lifting ability of the flying drones is required.

If several flying drones are clamped together and used to lift a load without a crane, the shared control system can keep the two flying drones at a distance from each other and fly together along a specific flight path to a destination. The flying drones can, for example, be attached to the common load via separate lifting ropes, or can also be attached to a common lifting yoke, to which the load is in turn attached.

In order to be able to provide sufficient lifting forces and pulling forces for the heavy loads carried by the flying drones during construction site operations, but at the same time also to enable the flying drone to respond sufficiently quickly to control commands and thus sensitive control of the lifting and/or pulling force and/or the flight path of the flying drone , the flying drones according to the invention each have a hydrostatic drive train for driving at least one rotor of the flying drone, such a hydrostatic drive train being able to comprise a hydrostat that works as a pump and can be connected to a drive motor, and one or more hydrostats that work as a motor can and can each be connected to a rotor in order to drive it and from as Pump working hydrostats are supplied. With such a hydrostatic drive train, the torque provided on a rotor and/or its speed can be varied very quickly by varying one or more hydrostatic manipulated variables in the form of the displacement volume of one or more hydrostats and/or the adjustment angle of one or more adjustable hydrostats. Such rapid adjustment of the torque and/or the speed is also available when working at a high performance level with large torques and/or high speeds in order to lift high loads.

If flying drones with multiple rotors are used, for example in the form of so-called multicopters, such a hydrostatic drive system enables the mentioned sensitive, rapid controllability of torque and/or speed individually for each rotor. In particular, several hydrostats can be provided, each of which is connected to one of the rotors in order to drive the respective rotor, so that the speed and/or the torque of the respective rotor can be adjusted individually by adjusting the respective hydrostat - which can be done individually.

Advantageously, the drive motor, which drives a hydrostat working as a pump, can be designed as an internal combustion engine, for example in the form of a diesel engine. Such an internal combustion engine can provide a sufficiently high performance, even over longer operating times, in order to achieve sufficient load capacities for the drone to lift larger loads.

It can be advantageous to operate the internal combustion engine mentioned in an at least approximately stationary operating state, in particular essentially at full load, at least while a lifting task is being carried out. The lifting and/or pulling force and/or the flight path of the flying drone can be controlled by adjusting a hydrostatic manipulated variable of the hydrostatic transmission or the hydrostatic drive train, in particular exclusively by adjusting one or more hydrostatic manipulated variables.

In an advantageous development of the invention, such a flying drone with a hydrostatic drive train can work together with a ground supply station, which can be coupled to the flying drone. In particular, such a supply station on the ground can include a cooling and/or filtering unit, which can be coupled to the hydrostatic supply circuit of the hydrostatic drive train and can cool and/or filter the hydraulic fluid of the hydrostatic drive train of the flight drone.

Alternatively or additionally, said supply station can also include a pressure source that can be coupled to the hydrostatic drive train of the drone and can bias the hydrostatic drive train, in particular can provide and/or set a desired target operating pressure there.

In order to adapt the control of the flying drones to the crane or to other flying drones in a simple manner and to make operation easy for the machine operator, the aforementioned common control device can have a main control unit with input means, from which control signals are sent to the at least on the basis of the movement requests entered a flying drone and/or the crane are generated and transmitted, and have an additional control unit from which control commands for at least one further flying drone are generated and transmitted depending on the flight or crane movements that were initiated by the main control unit. The additional control unit mentioned can be connected to the main control unit and designed to automatically generate control signals adapted to it for the additionally used flying drone depending on the control signals generated by the main control unit. For example, the additional control unit mentioned can include a sequence control module, by means of which the additional flight drone is controlled so that it The flight movements of a main drone automatically follow, without the machine operator having to specifically enter movement requests for the additional flight drone. Advantageously, said additional control unit can be designed in such a way that the additional flight drone can not only maintain a desired relative position relative to the crane or said main drone, but that said relative position can also be variably predetermined and changed, for example in such a way that said relative position continuously changed during a lifting process. For example, the additional control unit for the additional flying drone can specify a specific path relative to the crane that the flying drone flies during a lifting process or depending on the position of the load hook. For example, if an elongated carrier is lifted in an approximately horizontal orientation from a starting position initially parallel to the boom and this elongated carrier is to be placed at the destination by the crane boom in a twisted, for example approximately perpendicular, orientation to the vertical plane, the additional control unit can determine a flight path for the flight drone, which can, for example, have its starting point approximately vertically under the crane boom and then, in order to rotate the elongated support relative to the crane boom during the lifting movement of the load hook, can extend helically around a vertical through the trolley of the crane.

In order to enable easy operation of the flying drone, in a further development of the invention, the flying drone can also be controlled depending on a position of another drone in such a way that the flying drone automatically follows movements of a lead drone and at least approximately maintains a desired position relative to the lead drone even during lead drone movements .tried to keep and follows.

Advantageously, however, the flying drone can also be remotely controlled autonomously in such a way that the flying drone can freely fly to various desired positions in relation to the lead drone. Alternatively or additionally, however, the flying drone can also be flown completely freely relative to a guide drone, for example with the help of a joystick, in order to fly the flying drone until a desired relative position is reached. In an automatic mode, the common control device can then automatically hold or attempt to hold the relative position approached and follow any lifting movements of the lead drone.

In order to be able to position the flying drone relative to the lead drone and automatically track its movements, the flying drone can be position-controlled in a relative or lead drone-fixed coordinate system. For this purpose, a position determination device can be provided which determines the flight position of the Flight drone is determined continuously or cyclically relative to the lead drone, such a position determination device being able to have, for example, a signal locating device which can locate and/or evaluate signals coming from the flight drone and/or sent to the flight drone with regard to certain signal properties in order to determine the relative position of the flight drone to be designated as the lead drone.

Such a signal locating device can, for example, be implemented in such a way that several transceiver units are attached to the control drone, which communicate with a transceiver unit on the flight drone, so that from the signal transit times and / or signal strengths and / or signal directions in the sense of the connecting lines between the various crane or machine-side transmitter/receiver units to the transmitter/receiver unit of the flying drone whose position can be determined relative to the lead drone.

The transmitter/receiver units mentioned can be, for example, transponders or short-range transmitter/receiver units. In the case of a crane, the transmitter/receiver units mentioned can be attached, for example, to the boom, to the trolley, to the tower and/or to the load hook itself. In particular, the signal transit times from the respective transmitter/receiver unit on the crane or the machine to the flying drones and/or back from the flying drones to the machine-side transmitter/receiver unit can be determined and/or signal strengths can be recorded and/or the directions in which maximum signal strengths occur, are determined in order to determine the position of the flying drones relative to the crane from the signal transit times and / or signal strengths and / or signal directions of maximum signal strength.

Alternatively or in addition to such a relative position determination in a machine-fixed coordinate system, the positions of the

Flying drones on the one hand and the crane, in particular the load hook, or the guide drone on the other hand, each can be determined in an absolute coordinate system, so that the relative position can in turn be determined from the two absolute positions and in the manner described above, for example, the flying drones can be controlled in such a way that the flying drones automatically follow or attempt to follow a load hook or a guide drone and its movements.

The absolute position determination mentioned can be carried out, for example, by means of a positioning system, for example a GPS system. For example, the flying drones on the one hand and the load hook on the other hand can each be equipped with a GPS unit in order to determine, on the one hand, the absolute spatial position of the load hook and, on the other hand, the absolute spatial position of the flying drones. The spatial position of the load hook can also be determined approximately from the known movement and/or position data of the work machine components, such as the rotation angle of a tower crane, the trolley position and the load hook height, from which at least approximately, given a known installation location, in particular neglecting pendulum movements and /or wind influences, the load hook position can be determined.

In an advantageous development of the invention, the position control of the flying drones can also be controlled depending on work area limitations and/or construction site model data and/or obstacle detection data that can be obtained on the flying drones themselves.

Fig. 1:

eine schematische Seitenansicht eines Krans in Form eines Turmdrehkrans mit einer am Lasthaken angeschlagenen Last sowie einer zusätzlichen, mit der Last verbundenen Flugdrohne, eines nicht erfindungsgemäßen Beispiels,

Fig. 2:

eine schematische Darstellung zweier zusammengespannter, mit einer gemeinsamen Last verbundenen Flugdrohnen,

Fig. 3:

eine Frontalansicht des Krans aus Fig. 1 in einer Blickrichtung parallel zur Auslegerlängsachse, wobei zwei auf gegenüberliegenden Seiten des Lasthakens positionierte Flugdrohnen dargestellt sind, die mit der am Lasthaken angeschlagenen Last verbunden sind,

Fig. 4:

eine schematische Darstellung der gemeinsamen Steuereinrichtung zum Steuern eines Krans und der zusätzlichen Flugdrohnen zum gemeinsamen Heben einer Last, eines nicht erfindungsgemäßen Beispiels,

Fig. 5:

eine schematische Darstellung des hydraulischen Antriebsstrangs einer Flugdrohne nach der Erfindung, wobei weiterhin eine Versorgungsstation, an die die Flugdrohne mit dem hydrostatischen Antriebsstrang ankoppelbar ist, dargestellt ist, mittels derer der hydrostatische Antriebsstrang vorgespannt, gekühlt und filtriert werden kann,

Fig. 6:

eine schematische Darstellung der auf zwei Ebenen verteilten, insgesamt acht Rotoren einer Flugdrohne, die ebenenweise und in einer Ebene seitenweise unterschiedliche Drehrichtungen realisieren, und

Fig. 7:

eine schematische Darstellung der Steuerungshierarchie zum Steuern einer Flugdrohne.

The invention is explained in more detail below using a preferred exemplary embodiment and associated drawings. Shown in the drawings:

Fig. 1:

a schematic side view of a crane in the form of a tower crane with a load attached to the load hook and an additional aerial drone connected to the load, an example not according to the invention,

Fig. 2:

a schematic representation of two flying drones clamped together and connected to a common load,

Fig. 3:

a frontal view of the crane Fig. 1 in a viewing direction parallel to the longitudinal axis of the boom, with two flying drones positioned on opposite sides of the load hook being shown, which are connected to the load attached to the load hook,

Fig. 4:

a schematic representation of the common control device for controlling a crane and the additional flying drones for lifting a load together, an example not according to the invention,

Fig. 5:

a schematic representation of the hydraulic drive train of an aircraft drone according to the invention, further showing a supply station to which the aircraft drone can be coupled with the hydrostatic drive train, by means of which the hydrostatic drive train can be preloaded, cooled and filtered,

Fig. 6:

a schematic representation of the total of eight rotors of a flying drone, distributed over two levels, which realize different directions of rotation on each level and on one level, and

Fig. 7:

a schematic representation of the control hierarchy for controlling a flying drone.

How Fig. 1 shows, the crane 1 can be designed as a tower crane, the tower 2 of which carries a boom 3 on which a trolley 4 is movably mounted. The boom 3 can be rotated about an upright axis together with the tower 2 or without the tower 2 - depending on the design of the crane as a top or bottom slewing crane - for which a slewing gear drive is provided. The boom 3 could possibly also be designed to be luffed up and down about a lying transverse axis, with a suitable luffing drive, for example in conjunction with the Boom bracing could be provided. The trolley 4 mentioned can be moved using a trolley winch or another trolley drive. The drive devices mentioned can be controlled by a control device 5, which can include a stationary operating unit with suitable input means 19, for example in the form of joysticks in the crane operator's cabin 6 or at the control station of the crane or a remote control station and/or also have a mobile operating unit with appropriate input means can. Such a mobile operating unit can be designed, for example, in the form of a radio remote control that the crane operator can carry with him when he walks across the construction site in the crane work area in order to be able to control the crane outside the crane operator's cabin 6.

In order to be able to manipulate the load hook 8, which can be connected to a hoist rope 7 running from the trolley 4, or a load 20 picked up thereon in interaction with the load hook 8, at least one flying drone 9 is provided, which is connected to the load 20 and/or is connected to the load hook 8 by a pulling and/or pushing means, in particular a lifting rope or a push rod.

In order to provide a better overview of the manipulation task in addition to manipulating the load, at least one camera can be mounted on the flying drone, by means of which a camera image of the load hook 8 and/or the load hook surroundings can be provided. The said camera image is advantageously a live or real-time image in the sense of a television or video image and is transmitted wirelessly from the camera 10 of the flying drone 9 to a display unit and/or the control device 5 of the crane 1, the said display unit being, for example, a machine operator display according to Art a tablet or a screen or a monitor that can be mounted in the crane operator's cabin 6. If a remote control stand or a mobile control unit is used to control the crane 1 in the manner mentioned above used, said display unit 11 can be provided in the remote control stand or on the mobile control unit.

The flight drone 9 is provided with a remote control device 12, which allows the flight drone 9 to be controlled remotely, in particular to control the flight control units such as rotor blades in order to remotely control the flight position of the flight drone 9.

A corresponding remote control module is advantageously integrated into the control device 5 and/or can be provided in the crane operator's cabin 6 and/or the remote control stand or the mobile operating unit, for example equipped with corresponding joysticks.

How Fig. 7 shows, the control of the flight drone 9a; 9b include a flight computer 90, which can be provided on the flight drone and can include, for example, one or more microprocessors, one or more program memories and other hardware and / or software components in order to process a flight control program. How Fig. 7 further shows, said flight computer 90 can communicate with a ground station 110 via a communication link 100, for example a radio link, in order to transmit data from the flight computer 90 to the ground station 110 or vice versa from the ground station 110 to the flight computer 90. For example, telemetry data such as GPS position, rotor speed, lifting force and other drone parameters can be transmitted from the flight computer 90 to the ground station 110 in order to be monitored and/or evaluated there. Alternatively or additionally, data such as control signals can be transmitted from the ground station 110 to the flight computer 90 in order to influence the control of the flight drone there.

Said flight computer 90 can be operated by one on the flight drone 9a; 9b provided sensors 120 are supplied with sensor signals that indicate a current operating state of the flight drone and / or movement parameters specify, for example, a position signal such as a GPS position, air pressure, wind speed, compass data or similar.

Based on the sensor data from the sensor system 120 and/or based on the data received from the ground station 110, the flight computer 90 can execute or process flight regulation and/or control and control drives of the flight drone, in particular by a speed and/or a torque of a respective rotor to vary.

How Fig. 6 shows, the flight drone 9a; 9b have several rotors 120 to 127, which, for example, are arranged one above the other in two levels and can be arranged crosswise in each level. The drives of the rotors 120 to 126 and/or their drive gears are advantageously configured in such a way that rotors lying opposite each other in one plane - for example 120 and 122 as well as 121 and 123 - each rotate in the same direction, but rotors lying next to one another rotate in opposite directions. The directions of rotation in the two rotor planes can be reversed, so that a pair of rotors lying one above the other/beneath each other rotate in opposite directions to the two rotor planes, cf. Fig. 6 .

In such a multicopter, the flight movement and/or the provided load capacity or lifting and/or pulling load can be specifically controlled by the thrust distribution on the rotors, in particular by the speeds on the individual rotors 120 to 126 and/or their torque individually, in pairs or is varied in groups in order to cause the flight drone 9a, 9b to rise and/or fall and/or pitch and/or roll and/or yaw.

How Fig. 5 shows, the flight drone 9a; 9b according to the invention have a hydraulic drive train 130 for driving the rotors 120 to 127, wherein the hydraulic drive train 130 or the hydrostatic transmission can include a hydrostat 131 working as a pump, which can be driven by a drive motor 132. The drive motor mentioned 131 can advantageously be designed as an internal combustion engine VKM, for example in the form of a diesel engine or a gasoline engine or a gas internal combustion engine.

The hydrostatic drive train 130 further comprises several further hydrostats 133 and 134, each of which is drive-connected to one of the rotors 120 to 127 and can be supplied by the hydrostat 131, which works as a pump. In the Fig. 5 Only two hydrostats 133 and 134 working as motors are shown. However, it is understood that further such hydrostats working as motors can be provided in order to be able to drive the individual rotors that drive the flying drone 9a; 9b has. Such further hydrostats can be connected in particular in parallel to the hydrostats 133 and 134 shown with the supply and return lines, which are connected to the hydrostat 131 working as a pump.

According to the invention, the hydrostats 131, 133 and 134 mentioned are each designed as adjustable hydrostats whose displacement volume or pump power can be varied. For example, swashplate units can be used that are designed to be adjustable in the adjustment angle.

In order to control and/or regulate the torque and/or the speed of the respective rotor 120 to 127, the procedure can in particular be as follows: Advantageously, the drive motor 132 can be operated at least approximately constantly, for example under full load or at least approximately under full load or in an operating range that is favorable in terms of efficiency. The hydrostat 131 driven by the internal combustion engine 132 converts the rotary drive movement of the drive motor 132 into hydraulic pressure, which supplies the other hydrostats 133, 134. By adjusting the hydrostats 133 and 134 mentioned, the torque and/or the speed of the rotors connected to the drive can be varied. Additional hydraulic ones can also be used

Actuators are used in the hydrostatic drive train to control the rotors, for example via pressure control valves, mass flow throttles, etcetera.

How Fig. 5 further shows, the flying drone 9a, 9b can advantageously be coupled to a supply station 140, which can be installed on the ground or elsewhere, for example on the crane, in order to cool and/or filter the hydrostatic drive train of the flying drone and/or or to pre-stress in print. How Fig. 5 shows, the supply station 140 can have a pressure source 141, which can be coupled to the hydrostatic drive train, for example via a check valve and / or a check valve, in order to bias the hydrostatic pressure circuit to a desired target operating pressure.

Alternatively or additionally, the supply station may include a filtering device 142 and/or a cooling device 143, which is/are also connectable to the hydrostatic drive train in order to filter and/or cool the hydraulic oil when the aerial drone is coupled to the supply station 140.

In order to enable simple operation, the common control device 5 can have a main control device 5a with input means 19 for entering flight and/or crane movement requests, from which control signals are generated to the at least one flight drone 9a and/or the crane 1 based on the entered movement requests and transmitted, and have an additional control device 5b, from which control commands for the at least one and / or the further flight drone 9a; 9b are generated and transmitted depending on the flight or crane movements that were initiated by the main control device 5a.

Advantageously, the position of the flying drone 9 relative to the crane 1 and / or its load hook can be controlled largely autonomously and independently of the crane, at least in an autonomous control mode, for example in a manner known per se via the aforementioned joysticks of the remote control device 12. About The autonomous control module of the position control device 13 can be flown to a desired position of the flight drone 9 relative to the load hook 8.

In addition to such an autonomous position control module, the common steering device 5 or its additional control device 5b, in particular its position control device 13, can have an automatic sequence control module in order to achieve a predetermined position of the flight drone 9 - for example the desired position arbitrarily approached by the autonomous position control module and / or a predetermined, pre-programmed one Position - to be maintained, even if the crane 1 carries out crane movements and / or the load hook 8 is moved, so that the flying drone 9 largely automatically follows the load hook 8 and maintains the predetermined relative position.

A position determining device 18 is advantageously provided, which automatically continuously or cyclically determines the position of the flying drone 9 relative to the crane 1 and/or its load hook 8, so that the position control device 13 can control the flying drone 9 depending on the determined relative position.

For this purpose, the flight drone 9 can, for example, include a GPS unit 14, by means of which the absolute spatial position of the flight drone 9 is determined and transmitted to the position control device 13. On the other hand, the position of the load hook 8 can be determined so that the position control device 13 can remotely control the flying drone 9 to maintain the relative position.

The load hook position can in principle also be determined using GPS, for example by integrating a GPS unit into the load hook. Alternatively or additionally, however, the load hook position can also be determined from the position of the crane components, in particular calculated by the control device 5 of the crane, for example by detecting the angle of rotation of the boom, the position of the trolley 4 on the boom 3 and the unwinding length of the hoist rope 7, from which If the installation location of the crane 1 is known, the load hook position is different can at least be approximately determined if one ignores dynamic pendulum movements or wind influences.

Alternatively or in addition to such an absolute position determination, the position of the flight drone 9 can also be determined relatively in a coordinate system that is fixed to the crane, i.e. that rotates with the crane. For this purpose, transmitter/receiver units, for example in the form of transponder units 15, can be provided on the crane 1, for example on its boom 3 and its tower 2, possibly also on its trolley 4 and/or its load hook 8, which are advantageously located on several spaced apart units Places on crane 1 are attached. The above-mentioned transmitter/receiver units 15 can communicate with a corresponding transmitter/receiver unit 16 on the flight drone 9. For example, a locating device 17, which can be integrated into the control device 5 of the crane 1, can then determine the distances from the signal transit times of a signal between the transmitting/receiving unit 16 on the flying drone 9 and the respective transmitting/receiving units 15 on the crane 1 Flight drone 9 is determined by the respective transmitter/receiver units 15 on the crane 1 and from this the position of the flight drone 9 relative to the crane 1.

In addition to the position control mentioned, the common control device 5 can also include a lifting and/or traction control module, by means of which certain operating parameters of the flight drone 9a or 9b, such as rotor speed and/or angle of attack, are controlled so that the load-carrying device is at the Flight drone, for example a hoisting rope, which connects the drone to the load 20 or the load hook 8, is acted upon with a desired force, in particular with a specific amount of force and / or a specific direction of force.

For example, the tensile stress and/or the inclination ϕ of the mentioned hoist rope, which connects the drone 9 to the load 20, can be monitored relative to the horizontal using a suitable sensor system and, depending on this, the Flight drone can be controlled in order to pull the load 20 by means of the drone 9 in a certain direction with a certain strength or force.

How Fig. 3 shows, several flying drones 9a and 9b can also be connected to the load 20 or the load hook 8, whereby it can be advantageous, for example, to position at least one pair of flying drones 9a, b on opposite sides of the load hook 8 and with the load 20 or the Load hook 8 itself to be connected in order to be able to exert horizontal forces F _H in approximately opposite directions on the load hook 8 or the load 20 attached to it or to be able to compensate for each other if, for example, only the lifting ability of the flying drones 9a, b is required.

In addition to the above-mentioned connection of at least one flying drone 9 to a crane 1, it can also be advantageous for certain lifting tasks to only clamp several flying drones 9a and 9b together according to the invention and to lift the corresponding load with several flying drones, but without the crane or its load hook, as is the case e.g. Fig. 2 shows. In this way, for example, the range for a lifting task, which is limited by the radius of the crane 1, can be increased. Lifting a load 20 using only flying drones can also be helpful when setting up the crane 1, for example to lift certain crane components during crane assembly.

If several flying drones 9a, b are clamped together and used without a crane to lift a load 20, the common control device 5 can keep the two flying drones 9a and 9b at a distance from one another and fly together along a specific flight path to a destination. The flying drones 9 a, b can, for example, be attached to the common load via separate lifting ropes, or can also be attached to a common lifting yoke, to which the load 20 is in turn attached.

Claims (15)

1. Method for lifting a load (20), in which at least one aerial drone (9) carries at least a portion of the load (20) and the load (20) is connected to a further aerial drone (9b) and is partially carried and/or directed by the further aerial drone (9b), wherein the two aerial drones (9a, b) are controlled in coordination with each other by a common controller (5) for controlling flight movements, characterised in that a lifting and/or tensile force and/or a flight trajectory of the aerial drones (9a; 9b) is controlled by varying a rotor speed and/or a rotor torque, wherein the aerial drones (9a; 9b) each have a hydrostatic drive train (130) for driving at least one rotor (120-127) comprising at least one hydrostatic device (131) that operates as a pump and can be driven by a drive motor (132), and each have at least one further hydrostatic device (133, 134) that operates as a motor and can be connected to the rotor, and said rotor speed and/or rotor torque is controlled by adjusting a hydrostatic displacement volume and/or a hydrostatic swivel angle and/or a hydrostatic pumping capacity.
2. Method according to the preceding claim, wherein the load (20) is additionally connected to a load hook (8) of a crane and is partially carried and directed by the crane (1), wherein the aerial drones together with the crane (1) are controlled in a coordinated manner by a common controller (5).
3. Method according to any one of the preceding claims, wherein the common controller (5) has a main controller (5a) having input means (19) for inputting desired flight and/or crane movements, from which control signals are generated and transmitted to the at least one aerial drone (9a) and/or the crane (1) on the basis of the input desired movements, and has an additional controller (5b), from which control commands for the at least one and/or the further aerial drone (9a; 9b) are generated and transmitted depending on the flight or crane movements initiated by the main controller (5a).
4. Method according to any one of the preceding claims, wherein the drive motor (132) is designed as an internal combustion engine and is operated in an at least approximately constant operating state, in particular at least approximately in the full load range, wherein speed changes and/or torque changes on the rotor are controlled in a variable manner by adjusting the at least one hydrostatic device (133, 134; 131).
5. Method according to any one of the preceding claims, wherein the aerial drones (9a; 9b) are controlled such that a force (F) having a horizontal component (FH) is exerted on the load (20), wherein the aerial drones (9) are controlled such that the horizontal component (FH) counteracts a pendulum motion of the load (20) and/or counteracts a wind force.
6. Method according to any one of the preceding claims, wherein the aerial drones (9) are controlled such that the load (20) is rotated about a vertical axis while being lifted, wherein at least one aerial drone (9) is flown through the load (20) along an at least approximately helical path about a vertical axis when lifting the load (20).
7. Method according to any one of the preceding claims, wherein the aerial drones (9) are autonomously remotely controlled in an autonomous control mode, such that an aerial drone (9) approaches various predefinable positions relative to a guide drone (9a).
8. Method according to any one of the preceding claims, wherein specified operating parameters of each aerial drone (9), in particular rotor speed and/or rotor angle of attack, are controlled by the controller (5) such that a load suspension means on each aerial drone (9) connecting the aerial drone (9) to the load (20) is subjected to a specified force magnitude and/or a specified force direction, wherein the force directions of the different aerial drones point in different directions.
9. Device for lifting a load (20), in which at least one aerial drone (9) is connected to the load (20) by a load suspension means for carrying at least a portion of the load (20) and the load (20) is connected to a further aerial drone (9b), wherein a common controller (5) is provided for controlling the two aerial drones (9a, b) in coordination with each other, characterised in that a lifting and/or tensile force and/or a flight trajectory of the aerial drones (9a; 9b) can be controlled by varying a rotor speed and/or a rotor torque, wherein the aerial drones (9a; 9b) each have a hydrostatic drive train (130) for driving at least one rotor (120-127) comprising at least one hydrostatic device (131) that operates as a pump and can be driven by a drive motor (132), and each have at least one further hydrostatic device (133, 134) that operates as a motor and can be connected to the rotor, and said rotor speed and/or rotor torque can be controlled by adjusting a hydrostatic displacement volume and/or a hydrostatic swivel angle and/or a hydrostatic pumping capacity.
10. Device according to the preceding claim, wherein the load (20) is additionally connected to a load hook (8) of a crane (1) and the common controller (5) is designed to control the two aerial drones together with the crane (1) in a coordinated manner.
11. Device according to any one of the two preceding claims, wherein the common controller (5) has a main controller (5a) having input means (19) for inputting desired flight and/or crane movements, from which control signals are generated and transmitted to the at least one aerial drone (9a) and/or the crane (1) on the basis of the input desired movements, and has an additional controller (5b),which is configured to generate control commands for the at least one and/or the further aerial drone (9a; 9b) depending on the flight or crane movements initiated by the main controller (5a).
12. Device according to any one of the preceding claims 9 to 11, wherein the controller (5) has a position control device (13), which has an automatic follow-up control module for controlling the aerial drone (9) depending on a guide drone position in such a way that the aerial drone (9) automatically follows guide drone movements and maintains a desired position relative to the guidance drone even during guide drone movements, wherein the controller (5) is configured to control the aerial drones (9) such that one of the aerial drones (9) flies along a helical path about a vertical axis passing through the load (20) when lifting the load (20).
13. Device according to claim 10 or any one of claim 11 and 12 referring back to it, wherein a/the position control device (13) has an autonomous control module for autonomous remote control of the aerial drone (9) such that the aerial drone (9) approaches various desired positions relative to the crane and/or a load hook of the crane.
14. Device according to claim 10 or any one of claim 11-13 referring back to it, wherein a position determiner (18) for determining the position of the aerial drone (9) relative to a guide drone is provided, wherein a/the position control device (13) is deigned to control the aerial device (9) depending on the automatically determined relative position, wherein the aerial drone (9) has a GPS unit for absolute position determination of the aerial drone (9), wherein the position control device (13) for controlling the position of the aerial drone (9) relative to the crane is designed to control the aerial drone (9) depending on the absolute position data of the aerial drone (9) and the absolute position data of the crane, wherein the position determiner (18) has a signal locating device for locating a signal output by the aerial drone (9), wherein said signal locating device has mutually spaced transceiver units (15) attached to the crane for communicating with a transceiver unit (16) on the aerial drone (9), and an evaluation unit for evaluating the transmitted signals between the transceiver units (15) on a crane side and the transceiver unit (16) on a drone side, with respect to predetermined signal characteristics, in particular with respect to signal propagation time and/or signal strength, and for determining the position of the aerial drone (9) relative to the crane (1) from the signal characteristics.
15. Device according to any one of the preceding claims 9 to 14, wherein an internal combustion engine (VKM) is provided as a drive motor (132), wherein the aerial drone (9) is designed as a multicopter and has a plurality of rotors, wherein the hydrostatic drive train (130) comprises a plurality of hydrostatic devices (133, 134) operating as motors, which are each drivingly connected to a respective rotor, and are individually adjustable to individually control the speed of the rotors connected to the respective hydrostatic devices.

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